I have a question related to the discretization of the dispersed phase in the Mixture Model, Laminar Flow interface. Under "Discretization" is only possible to choose the discretization for the fluid phase, while for the solid phase (i.e. phid) is not.

Do you know which discretization is used for the solid phase? Is it linear?

Any idea on why it is not possible to choose the discretization for the solid phase?

Thanks J for pointing this out. Yes phid follows the discretization order of the pressure not the velocity. That selection results in a more diffusive yet more stable scheme. It would be nice to have the option in COMSOL to select an independent discretization order for phid. You can still do that now if you manually (and properly) couple two separate physics fields; single-phase laminar flow and transport of species.